[rst]

If the libraries were missing entirely, I'm not sure 32-bit Firefox would even start. But if they were present and nothing was keeping them updated (pretty likely on an otherwise 64-bit system), they'd pretty likely become out of date -- which could certainly explain spurious crashes.

[capitainenemo]

Fair point, although Firefox also launches subprocesses, and I don't know if those use same libraries as the main process. And I also don't know if it dynamically loads supporting libs after launch.

[ars]

No, this is Debian, it keeps the 32 bit libraries just as in-date as the 64 bit ones. It can handle having both at the same time.